Heater Core Flush?

[Phoenix69]

When you flush your entire system i thought your radiator would be flushed as well? I'm a noob.

[Phoenix69]

Also, I've heard of getting a cracked upper plenum resulting in coolant leaking into engine for my 3800 series II. Also that certain gaskets are corroded over time and cause specific leaks. I was wondering if any of these coolant flushers/cleansing chemicals would damage the gaskets or if they are safe to use.

[blazee]

Originally Posted by Phoenix69

Also, I've heard of getting a cracked upper plenum resulting in coolant leaking into engine for my 3800 series II. Also that certain gaskets are corroded over time and cause specific leaks. I was wondering if any of these coolant flushers/cleansing chemicals would damage the gaskets or if they are safe to use.

The chemicals shouldn't hurt the gaskets, HOWEVER if you gasket is deteriated connecting a water hose and turning it on high pressure will.

You system runs at around 16psi, a normal water hose is around 40psi. If it leaks at 16 just imagine what it will do at 40.....

[Phoenix69]

AHhhh...

[Phoenix69]

Any easy roundabout way i can check for such leaks? or do i just have to hope for the best?

[blazee]

Not wanting to sound like a smartass, but... the best way to tell if you have a leak is to check you coolant level. If it is low or you have to add regularly then you have a leak. From what I have read on the forums of AF alot of the leaks can be seen by inspecting around the intake.

[Phoenix69]

Hm, no offence taken, i'm still learning about cars having got my first one not too long ago and am trying to fix things.

[blazee]

According to chevy a system in good condition will withstand up to 50psi, but I would never go higher than neccessary to remove the blockage. A reverse flush doesn't require much pressure to clear the system. I have had great success at pressures closer to 20psi and didn't have to jeopardize the system.

[Phoenix69]

In your name tag here i see youve worked on your rotors, i just noticed on one of mine that it has a 1/16 or 1/8 inch deep line carved into it about the width of a penny. What could have cause this and should i get it checked out?

[Rick Norwood]

Originally Posted by Phoenix69

Any easy roundabout way i can check for such leaks? or do i just have to hope for the best?

The easiest way to check for cooling system leaks is to go to Autozone and borrow the Pressure Cap tool. It is a Radiator cap with a small tire pump on it. When your engine is cool and turned OFF, you remove your Radiator cap, make sure your coolant is topped off and install the pressure cap tool. Pump the pump to approx. 15-16 lbs pressure and look for any leaks. Have a flashlight handy and an inspection mirror if you have one. This will safely allow you to see even the tiniest leaks unless they are hidden from view like in the heater core. After that, it is like Blazee says, "Watch your coolant level".

[Rick Norwood]

Originally Posted by blazee

The chemicals shouldn't hurt the gaskets, HOWEVER if you gasket is deteriated connecting a water hose and turning it on high pressure will.

You system runs at around 16psi, a normal water hose is around 40psi. If it leaks at 16 just imagine what it will do at 40.....

I'd like to comment about the "Garden Hose Flush"

The basic concept here is to FLUSH the system, not to PRESSURE TEST the system.

When ever I use a garden hose to flush a system, I ALWAYS leave the water a way to escape. I NEVER try to build up pressure by sealing off all of the openings.

If I am trying to flush the heater core for example, I alway disconnect BOTH heater hoses, attach the garden hose to one side and let the water FLUSH the core out through the other side.

I also like to attach the garden hose to the heater hose that that comes out of the top of the block, however, when I do, I remove the lower radiator hose from the radiator, and flush the crud out of the block and not into the radiator.

I also like to remove both radiator hoses and wrap a rag around the garden hose and flush the radiator out going in both directions.

BUT THE WATER ALWAYS HAS A WAY TO ESCAPE.

I have performed the above mentioned flush on countless vehicles over 35 years of mechanical work and NEVER caused any damage, blown out any gaskets, ruptured any radiators, ruined any heater cores, or created any bigger problems than were already there. In fact this has worked great for me and I have always ended up with a good clean system.

The word of the day here is caution and common sense. If you don't feel comfortable doing this type of flush, don't do it.

Peace to all and good luck.

Rick

[blazee]

Originally Posted by Phoenix69

In your name tag here i see youve worked on your rotors, i just noticed on one of mine that it has a 1/16 or 1/8 inch deep line carved into it about the width of a penny. What could have cause this and should i get it checked out?

Check you pads, it may be time for new brakes. If the gash is that deep you will need to replace the damaged rotor. I highly recommend you replace the one on the other side as well.

[blazee]

Originally Posted by Rick Norwood

I'd like to comment about the "Garden Hose Flush"

The basic concept here is to FLUSH the system, not to PRESSURE TEST the system.

When ever I use a garden hose to flush a system, I ALWAYS leave the water a way to escape. I NEVER try to build up pressure by sealing off all of the openings.

If I am trying to flush the heater core for example, I alway disconnect BOTH heater hoses, attach the garden hose to one side and let the water FLUSH the core out through the other side.

I also like to attach the garden hose to the heater hose that that comes out of the top of the block, however, when I do, I remove the lower radiator hose from the radiator, and flush the crud out of the block and not into the radiator.

I also like to remove both radiator hoses and wrap a rag around the garden hose and flush the radiator out going in both directions.

BUT THE WATER ALWAYS HAS A WAY TO ESCAPE.

I have performed the above mentioned flush on countless vehicles over 35 years of mechanical work and NEVER caused any damage, blown out any gaskets, ruptured any radiators, ruined any heater cores, or created any bigger problems than were already there. In fact this has worked great for me and I have always ended up with a good clean system.

The word of the day here is caution and common sense. If you don't feel comfortable doing this type of flush, don't do it.

Peace to all and good luck.

Rick

right. you alway leave the cap off and the drain open while flushing.

The point isn't that the system develops high pressure, it is that the water is going in at high pressure.

[blazee]

Originally Posted by Rick Norwood

The easiest way to check for cooling system leaks is to go to Autozone and borrow the Pressure Cap tool. It is a Radiator cap with a small tire pump on it. When your engine is cool and turned OFF, you remove your Radiator cap, make sure your coolant is topped off and install the pressure cap tool. Pump the pump to approx. 15-16 lbs pressure and look for any leaks. Have a flashlight handy and an inspection mirror if you have one. This will safely allow you to see even the tiniest leaks unless they are hidden from view like in the heater core. After that, it is like Blazee says, "Watch your coolant level".

That is an easy way to locate leaks, but not to determine if you have a leak. The best way to determine if you have a leak is to check your coolant level.

[Rick Norwood]

Originally Posted by blazee

right. you alway leave the cap off and the drain open while flushing.

The point isn't that the system develops high pressure, it is that the water is going in at high pressure.

I guess I just don't see a problem with that. A large volume of water is going in at a higher pressure, yes, but isn't that the purpose of a flush?

Water, like just about everything else, will follow the least path of resistance, if water is slowly added into a system, a clogged tube will simply force the water into an open tube, and pockets of crud will probably remain pockets of crud. The desired result is to dislodge and move pockets of crud out of the system and possibly open up partially clogged radiator tubes.

As I stated in earlier threads, nothing beats a properly performed Reverse Power Flush, but if you're low on funds, this might just get you through another season. I have never seen anything damaged as a result of using a garden hose to flush a cooling system.